Brake



April 15, 1947. H. PERROT 2,418,848

BRAKE Filed May 20, 1942 2 Sheets-Sheet 1 HfNE/ PER/E07 ATTOJE/VEY April 35, m7. H. PERRQT V 2,418,848

BRAKE F'iled May 20, 1942 2 Sheets-Sheet 2 mvewraz I HE/y/P/ PEEEOT ATTOENEY Patented Apr. 15, 1947 OFFICE.

2,418,848 BRAKE Henri Perrot, Paris, France; vested in the Attorney General of the United States Application May 20, 1942, Serial No. 443,791

The invention relates'to brakes and more particularly to brakes in which the applying means comprises a wedge acting on the brake shoes through the intermediary of a roller and links assembly.

One object of the inventionis-to provide a brake applying means forming an independent unit, the members of which cannot be separated one from another in spite of the relative movement of said members during the operation of the brake.

Another object of the invention is to provide a brake applying means including a wedge adapted to spread one from another a pair of links operatively connected to the brake shoes while upon release of the brake the return stroke of the wedge brings positively said links to normal position independently of the return of the brake shoes.

France January 29, 1941 8 Claims. (Cl. 188-78) Figures 7 and 8 are similar to Figures 1 and 2, and show an embodiment of the improved applying means.

Figure 9 is a view of a brake provided with an applying means shown inFigures 'l and 8, and

- in which the left hand part of the cover carried A still other object of the invention is to pro- A brake provided with an adjusting means acting as an anchorage for the brake shoes and in which the adjustment of the anchorage is efiected by rotating an accentrie member through which extends a projection or the casing in which is located the adjusting means. d

Other objects and advantages of the invention will be apparent from the following description, wherein reference is made to the accompanying drawings, in which:

Figure 1 is a view in section of the improved applying means shown in normal position.

Figure 2 is a view similar to Figure 1 andshows the applying means in a position corresponding to the end of its operating stroke.

Figure 3 is a view of a brake including the applying means shown on Figures 1 and 2, and in which the cover of the casing, in which is located said applying means, is removed.

Figure 4 is a vertical section on line 4-4 of the brake shown in Figure 3.

Figure 5 is a section on line 5-5 of the adjusting means shown inFigure 3, the left hand part of the figure showing the adjusting means in its initial position, while the right hand part of the figure shows the adjusting means in a position which corresponds to the end of its stroke.

Figure 6' is a view of an emergency applying by the casing enclosing the applying means is re moved.

Figure 10 is a vertical section on line ill-l0 oi the brake shown in Figure 9.

Figure 11 is a section on line lll I of the adjusting means shown in Figure 9, the left hand part of the figure showingthe adjusting means in its initial position, while the right hand part of the figure shows the adjusting means in a position which corresponds to the end of its stroke.

Figures 12-, 13 and 14 show positioning means for brake shoe rims.

The brake illustrated in Figures 1 to 6 comprises a backing plate 2 and brake shoes 4 and 6 adapted to be brought into contact with a rotating drum 8 under the control of an applying' means indicated generally in Ill. The applying means includes a wedge 12 adapted to reciprocate in a plane perpendicular to the backing plate and shown as being integrally made with an operating rod l4 actuated b a fluid pressure responsive cylinder indicated generally in It. The wedge l2 acts on the brake shoes 4 and 6 through the intermediary of links l8 each formed on its inner end with a short projection 20 and a longer projection 22 between which extend the'respective operating faces of the wedge. The links i8 are of identical construction, and the position'"of these links is inversed on the wedge i2, so that the projection 20 and a longer projection 22.

of operating rollers 24 and 26 mounted on pins 28 and 30 which extend through the projections formed on the links.

A pin 32 carried by the wedge projects into a slot 34 formed in the longer projections 22 and arranged in such a manner that the displacement of pin 32 in said slot, upon forward movement of the wedge, is not hindered by the spreading movement of the links operated by said wedge. The slot 84 is formed with an inclined ramp 36 which, on each of the-projections 22, is arranged parallel to the operating surface of the wedge acting on the respective link.

In case the brake shoes would, for some reason,

fail to return upon release of the brake, the links 18 will positively be brought to normal position by the wedge. As the wedge initiates its return 3 stroke under the action of return spring 38 which takes support on a metal cup 40 carried by the operating rod M, the pin 32 slides on the inclined ramp-I8 provided in the longer projections 22 and thus urges the links I! to normal position bringing them one closer and closer to the other, until they come into the position shown in Figure 1. The pin 32 is preferably secured to the wedge l2 by means of a cotter pin 42, which takes secured to the backing plate 2 by means of bolts ll extending through openings formed in its base and through corresponding openings 50 provided in the backing plate. n the bolts are mounted nuts 52 which, as shown in Figure 1, engage a Y depression formed in the backing plate and lock the casing in place. The base of the casing is also formed with a central opening 54 through which extends with play the operating rod I4. The lateral walls of the casing may be formed, as shown in Figure 3, with reinforcing ribs 58 and the edges of these walls may be shaped to provide guides 58 substantially parallel to the backing plate on which move the pins 28 and 30. The marginal portions of the casing walls are bent parallelly to the backing plate and in each of said portions there are formed circular openings 80. On the casing 48 is secured a cover 62 the inner face of which acts as a rolling table for supporting rollers 64 mounted in pairs on the pins28 and 30 extending through the links. The rollers 64 are mounted on opposite sides of the links, preferably with interposition of distance washers N, and said rollers are kept in place by means of split rings GI mounted in grooves, formed at the outer ends of the pins 28 and 30. When the wedge I2 is moved forwardly, the operating rollers 24, 28, engaged thereby spread the respective links apart and the reaction forces are transmitted to the cover 62 through the intermediary of the supporting rollers 84 which roll, in operation,

on the inner face of the cover. The latter is provided with marginal bent portions 10 corresponding to the bent portions formed on the cover. In the marginal sections 10, there are provided elongated openings 12, the middle position of which corresponds to that of the openings 80, and bolts H extending through these'openings serve to secure the cover to the casing. As shown in Figure 4, on the bolts 14 are mountednuts 18 and the head of these bolts is formed with a flat engaging the casing wall, so that the position of these bolts cannot be altered by vibrations inherent to the motion of the vehicle.

4 mounted flo'atingly. so that it can move in either direction. The wedge can thus follow the brake shoes in their displacement and compensate the difierence in the wear of the linings mounted on the shoes.

The longer projection 22 is formed with 0. lug 8| having a shape complementary to that of the adjacent short projection 20 and a suitable play is left between these projections. The outer link ends are formed with slots 82 into which project the webs of the shoes 4 and 8. It will be noted that a play is left between the outer edge of the links and the adjacent wall of the cover, while the inner edge of the links also clears the walls of the casing. Thanks to this arrangement, even in case the links I! were covered with a layer of rust, no locking eflect can take place since the links are suspended in the air.

The outer ends of the links II are provided with abutments N, which take support on the opposite ends of the cover, beyond the plane in Since the openings 12 formed on the cover Q are elongated in the longitudinal direction, it is possible, by loosening the nuts 16, to adjust the position of the cover with respect to the casing,

thus enabling a factory adjustment of the brake to be made, which adjustment is intended to compensate the manufacture clearances which are unavoidable in the practice. The cover 62 is 7 which extend the shoe .webs. which are connected one to the other by return springs 88' and 88, so that the component resulting from this overhanging eifect tends to urge, in normal position,

the links, the supporting rollers and their pins. 7 into contact with the cover, to lock them in position, thus avoiding any clicking noise during the motion of the vehicle.

It results from the foregoing that if for some reason, the brake shoes would lag to return to normal position, the links would not become disassembled from the applying means assembly; the interlock between these members is due to the fact that theoutward pivoting of the links on the pins 28 and 30 is limited due to the fact that the edges of the links extend closely to the ,cover 62, while the inward pivotingof the links is limited by engagement of the lug formed on one link with the shorter projection 20 of the other link. The applying means thus forms an independent unit, the members of which are kept in place without any possibility of leaving the unit, in spite of the relative displacement of these members in operation.

The wedge i2 can be manufactured by drop forging and formed on each side with a recess ll of trapezoidal shape which facilitates the provision of straight surfaces adapted to slide between the forked projections of the links. As shown on Figure 3, in order to eliminate the friction of the sides of the operating rollers 24. 26 on the inner walls of the forked links l8. these rollers are formed with a chamfer 89 on the ma- Jor part of their sides.

In order that the brake shoes maybe kept in proper lateral position with respect to the backing plate, there are provided return springs 82 inserted on pins 90 which pass through openings formed in the backing plate and corresponding openings provided in the brake shoe webs. The return springs take support on a metal cup 84 mounted at the end of the pin 80 and on a cup 96 which takes support on the brake shoe web. In order to assist the mounting of the springs, the cups are formed with rectangular slots 98 through which are inserted flattened heads I00 provided on the pins so that by rotating the pins a quarter of revolution, the flattened heads are seated into a recess illl formed in the cup 94 perpendicularly to the slot 98 thus locking the spring in the place.

The operating wedge is preferably actuated by a fluid pressure responsive cylinder l6 perpendicular to the backing plate and arranged outwardly, so that the cylinder is subject to an. in-

tense cooling being swept by a stream of air which isicreated by the motion of the vehicle.

The cylinder I6 is provided with an inlet port I02 and a bleeding port I04 which is closed in normal position by a bleeding screw I08.

A piston IIO mounted in the cylinder is formed with a central projection II2 which, in normal position of the hydraulic system, takes support on the cylinder head, under the action of the return spring 38 acting on the operating rod Id. The projection H2 is formed with a slot H which registers with the feeding port I02 so that in normal position, the fluid pressure responsive cylinder I0 is connected to the piping of the hydraulic system. An annular scaling cup IIB, made of rubber, is inserted in a groove I formed on the projection I I2. The object of this cup is to prevent seepage of liquid along the piston.

The angular position of the cylinder It can be adjusted so that in any position of the applying means on the backing plate, the bleeding port I00 can be arranged on the top of the cylinder.

The wheel cylinder is preferably mounted through the intermediary of a cross member I22 which acts as a seat for the return spring 38. The cross member I22 takes support on one side of an annular shoulder I24 formed on the cylinder, while the opposite end of this shoulder takes support on a bracket I20 preferably secured in place by means of the bolts 40 which serve for securing the casing 46 to the backing plate, The bolts 40 pass through openings I28 formed in the bracket and on the ends of these bolts are mounted nuts I30 by means of which the cylinder I0 is firmly secured to the backing plate. By dismounting the nuts I30, the cylinder can be easily removed, and it is possible therefore to replace a cylinder of one diameter by a cylinder of another diameter, thus increasing the range of vehicles adapted to be equipped with the brake forming the object of my invention. The fiuid pressure responsive cylinder is separated from the operating wedge by a rubber cover I32 inserted on the one hand on the rod I4 and on the other hand on the end of the cylinder.

The brake shoe ends opposite to the applying means take support on an adjusting screw I34 through the Intermediary of plungers I36 locatedin a casing I38. This casing is mounted on the backing plate, such as bymeans of .screws I40 which extend through cooperating openings formed in the backing plate and in the casing. The plungers I36 are provided with beveled ends I42 which cooperate with notches I44 formed on the beveled head of the adjusting screw I34.

When the brake linings are new, the adjusting screw I35 is in the position shown on the left hand part of Figure 5, and as the linings become worn, the screw is rotated for one or more notches, for instance by means of a key inserted on a square I45 formed on the outer end of this screw. The adjusting screw I34 is thus driven further and further into the casing I38, whereby the plungers are spread one from another enabling to keep when the brake is released, a normal play between the shoes and the brake drum. The adjusting screw I34 carries an abutment ring I48 which, in a position corresponding to the end of the stroke of the adjusting screw, takes support on a boss I48 formed in the casing, thus limiting any further advance of the screw. It

results therefrom that when the liningbecomes 50 with the head of the cylinder.

completely worn out, the brake shoe rims cannot wear out due to friction against the periphery of the drum.

The plungers I30 are formed, at their outer ends, with slots, the bottom of which forms an inclined plane on which take support the respective brake shoes through the intermediary of a trunnion I 52 formed with a corresponding inclined plane, as described in U. S. application in Serial No. 279,266, now Patent No. 2,269,268, Jan.

6, 1942. Each trunnion is located in a corresponding recess formed on the end of the brake shoe web. Thanks to this arrangement. the braking torque transmitted by the shoes is reis ceived by membgs having an area suflicientto resist an important load, while allowing the shoe to rock freely about its end.

Besides the fluid pressure applying means described above, the brake is provided with a mechanical applying means illustrated in Figure 6 and which includes a lever I04 passing through an opening I66 provided in the backing plate and which is formed with a rounded projection I50 taking support on the web of the brake shoe link I02 providedat its end with a slot I04 into which projects the web of brake shoe 4. On the outer end of the lever I54 there are provided one or several openings I06 for attachment of the end of a cable or rod connected to the hook-up operated by the hand lever. When the hand lever is put into action, the brake shoe 3 is pressed against the drum and forms an abutment for the lever I54 acting on the link I82, as a result of which the other brake shoe is likewise applied against the drum. The lever I54 projects through a cover I closing the opening I50, and this cover is applied against the backing plate by means of a leaf spring I kept in place by a cotter pin I10 which passes through an opening formed in the lever I54.

It results from the foregoing that when the brake shoes are brought into contact with the drum by the mechanical applying means, this 45 operation does not affect the fluid pressure operated cylinders due to-the fact that the piston I I0 is kept immovable by the return spring 30 which acts on the operating rod I4; the piston projection H2 is therefore kept in engagement There is thus eliminated the creation of a detrimental vacuum which could tend to take place in case the actuation of the mechanical applying means should affect the hydraulic applying means.

' The embodiment illustrated in Figures 7 to 11 is similar to that descrlbed'above and the similar members in said figures are indicated by same 60 carries, such as by means of a pin, a slide I12 with two inclined ramps I14 of opposite directions which are parallel to the inclined operating faces of the wedge. with a pin I18 carried by the forked links I0.

It results from the foregoing that to each stage of spreading of the links, there correspond sections of the slide I12, which are removed more and more one from another, so that when the wedge I2 is brought to the end of its operating 0 stroke by the fluid pressure responsive cylinder I8, thepins I13 are in contact with the member I10 which connects the inclined ramps, as illustrated in Figure 8.

When the brake is released. the slide I12 brings 7 5 back the links upon the return movement of the 8. The lever IE0 is connected by a pin I30 to a Each of these ramps is engaged 8 7 wedge, drawing together the pins I18 by means of the inclined ramps I14, thus bringing them one adjacent the other.

In the embodiment illustrated in Figures '1 to 11, the pins 28 and 88 carry the operating rollers 24, 28 and two pairs of supporting rollers 84 adapted to roll in operation on the innerface of the cover I8 and the pins 28 and 88 are adapted to move in alined longitudinal slots I88 formed in the walls of the casing 48. The outer ends of the links I8 are forked and form a slot parallel to the backing plate in which project the webs of the respective brake shoes. Pins I82 which extend through alined openings provided in the forked ends of the links are formed with heads which in normal position seat in recesses I84 at the ends of the cover. Due to the fact that the heads of these pins take support on the cover in a plane extending beyond the plane in which act the return springs 88, 88 inserted between the brake shoe webs, a component is created which, in normal position of the brake, urges the links,

with the supporting rollers 84 into contact with the inner face of the cover. The assembly formed by the supporting rollers 84, their pins 28, 88 and the links I 8, is therefore locked in place in normal position of the brake, thus suppressing any clicking noise when the vehicle is in motion. As the brake is set into action, the pins 28 and 88 clear the edges of the cover and the supporting rollers 84 roll freely on the rolling table formed by the inner face of the cover, thus insuring an efilcient operation of the applying means. As already indicated for the first embodiment, under action oi the load, the assembly formed by the links, the operating rollers 24, 28 and the wedge, is alined in one plane, thus avoiding any wedging effect.

The brake embodiment illustrated in Figures 7 to 11 is provided with an adjusting means similar to that shown in Figure 5 with this diiference, however, that it comprises novel means for adlusting of casing I38 in the plane in which the plungers I88 act on the respective shoes. The casing I38 is located in a cylindrical eccentric member I88 mounted in an, elongated vertical opening I8I. The casing I38 is secured to the backing plate by means of screws I48 which errtend through elongated openings I88 provided in the backing plate. It results from the foregoing that by rotating the eccentric member I88, after having previously loosened the screws I48, the position of the casing is adjusted in the plane in which act the plungers, while the eccentric member I88, adjusts its position in the elongated opening .I8I, being kept in linear contact with the walls of said opening. The eccentric member I88 is formed on its outer side, for instance with a hexagonal section I88 projecting into a complementary opening provided in a plate I92 immobilized by means of a screw I94 secured to the casing. The screw I 84 extends through an arcuate slot I88 formed in the plate, in order that the latter could shift with the eccentric member I88 when one proceeds to the adjustment of the position of the casing on the backing plate. When the adjustment is completed, the screw I84 is fixed in place thus immobilizing the eccentric member I88 through theintermediary of the plate I82.

A suitable choice of the position of the adjusting means on the backing plate enables to compensate manufacture clearances, which is realised in the first embodiment by adjusting the position of the cover 82 on the casing 48.

It is to be noted that the attachment of the 08.8-

brake shoe rims take support either directly in' a recess I88 provided in the backing plate, as illustrated in Figure 14, or on stops 288, of variable height, as shown in Figures 12 and 13. The use of stops of variable height enables to use the same backing plate for brake shoes and drums of various widths. The stops 288 can be riveted to the backing plate and mounted at the end of a his 282, the opposite end of which is secured to the backing plate such as by means of a rivet 284.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

What I claim is:

l. A brake comprising two shoes, a brake drum, a wedge operatively connected with the shoes for expanding the latter into contact with the drum upon operative stroke of the wedge. links forming part of the operative connection, and means acting through the wedge for returning the links to normal position independently of the return of the shoes upon retractile stroke of the wedge.

2. A brake comprising two shoes, a wedge operatively connected with the shoes, links formingpart of the operative connections, a forked porjections of diflferent lengths and arranged above and below the wedge, and meansinterlocking the projections with the wedge for positively bringing back the links to normal position upon the return movement of the operating wedge.

4 3. A brake comprising friction means, a wedge operatively connected with the friction means, a link forming part of the operative connections, a forked portion on the inner end of the link comprising a longer projection arranged at one side of the'wedge and a shorter projection arranged at the opposite side of the wedge, a slot in the longer projection formed with a ramp parallel to the adjacent operating face of the wedge, and means carried by the wedge and engaging the ramp. 8

4. A brake comprising friction means, a wedge operatively connected with the friction means, links forming part of the operative connection, a forked portion in the inner end of each link comprising a longer projection arranged at one side of the wedge and a shorter projection arranged at the opposite side of the wedge, a slot in the longer projection formed with a ramp parallel to the adjacent operating face of the wedge and means carried by the wedge and engaging the ramps on opposite sides of the wedge.

5. A brake comprising friction means, an operating wedge operatively connected with the friction means, links forming part of the operative connection, a slide carried by the operating wedge, and means interlocking the slide with the 6. A brake comprising friction means. an opwithin the casing for positively returning the eratlng wedge, links connecting the friction means with the operating wedge. a slide carried by the operating wedge, a pair of ramps provided on the slide and respectively parallel to the operating faces of the wedge, and means carried by the links and engaging the ramps.

7. A brake comprising friction means, a brake drum. a backing plate. an applying means operatively connected with the friction means. links forming part of the operative connection. a casing secured'to the backing plate and enclosing the applying means and the links, and means within the casing interlocking the applying means and the links.

8. A brake comprising friction means, a brake drum. a backing plate, an applying means operatively connected with the friction means, links forming part of the operative connection for bringing the friction means into contact with the drum as the applying means is set into action, a casing secured to the backing plate and enclosing the applying means and the links, and means links to normal position as the applying means is set out of action.

HENRI PERROT.

REFERENCES CITED The following references are of record in the file of this patent; UNITED s'm'ms PATENTS i Number Bryan Apr. 24, 1923 

